The field of the proposed invention relates to the manufacture and assembly of printed wiring boards (PWBs) and more particularly to methods, equipment, and improved printed wiring boards in which multiple boards can be manufactured, connected, and tested together before separation into adjoining boards.
The electrical joining of multiple PWBs is a common feature in many computers and in much additional modem electronic equipment. PWBs are typically joined by orthogonally mounting one board into a socket fixture connected to an adjoining board. Such orthogonal mounting allows the PWBs to occupy less space within the same plane, thereby more compactly using the available cabinet space.
Whenever separate PWBs are joined, they must be both electrically connected and held rigidly in position in relation to each other. Both functions are often provided by a socket fixture. Although wire connections separate from the socket fixture are well known in the art, the typical socket fixture both holds the joined boards rigidly in position in relation to each other and provides electrical connection for each circuit that runs from one board to the other. To accomplish such electrical connections, it is necessary for circuits within the socket fixture to be aligned precisely with the relevant circuits on each board and then, typically to be soldered at the circuit juncture on each board in order to assure good electrical contact and rigidity at the point of electrical contact. Where separate wires are used for electrical contact between the boards rather than circuits within the socket fixture itself, such wires have conventionally been manually soldered using pre-insulated wires. The process of joining the boards typically requires manual insertion of at least one of the boards into the socket fixture in order not to damage pins or edges of the inserted board.
FIGS. 1-2 show two conventional socket fixtures of the prior art. Beginning with FIG. 1, an elevational cross sectional view of socket fixture 11 is shown joining two PWBs in an orthogonal fashion. Socket fixture 11 is mounted on top of base PWB 10 by means of soldered fasteners 12A and 12B. The cross sectional view of socket fixture 11 reveals that the fixture has a u-shape receptor into which orthogonal PWB 13 is inserted. Electrical connections to base PWB 10 are made by contact pins 15 at the base of socket fixture 11 where it is fastened to base PWB 10. Often, soldered fasteners 12A and 12B also serve as the electrical contacts, and the holes into which they are inserted are drilled into PWB electrical contact pads of the type discussed below in relation to the improved process of the present invention. Returning to FIG. 1, electrical connection between socket fixture 11 and orthogonal PWB 13 is made by contact pins 14 (shown in dotted outline) extending beyond the edge of PWB 13. Pins 14 are inserted into pin sockets at the base of the unshaped receptor of fixture 11. During manufacture, both PWBs 10 and 13 are printed separately. Although the placement and attachment of socket fixture 11 to base PWB 10 is often automated, the insertion of PWB 13 into socket fixture 11 is done manually to avoid damaging pins 14.
Turning now to FIG. 2, a second example of a conventional socket fixture is shown. Here, socket fixture 21 comprises a straight connector that is placed into pre-drilled holes and soldered into base PWB 20 using soldered fasteners 22, which may also serve as electrical contacts. The structural and electrical connections between fixture 21 and base PWB 20 are thus the same as shown in FIG. 1. Instead of a unshaped receptor, however, fixture 21 mates with orthogonal PWB 23 by a repeat of the processes used to fasten fixture 21 into base PWB 20. In other words, orthogonal PWB 23 is aligned parallel to and in contact with socket fixture 21. Fasteners 24A and 24B are then inserted into pre-drilled and aligned holes in both orthogonal PWB 23 and socket fixture 21. When soldered into place, fasteners 24A and 24B both rigidly hold PWB 23 orthogonally to base PWN 20 and provide electrical contact between the PWBs.
As noted above, stacked PWBs, whether stacked orthogonally as shown in FIGS. 1 and 2 or otherwise, require hand manipulation during assembly. Often, the hand manipulation extends to selection from inventory of the correct boards for assembly since each board is manufactured independently of the other. A further consequence of conventional manufacture and assembly processes is that each board undergoes its own manufacturing and handling processes independent of the other. In other words, each of the manufacturing, assembly, and testing processes of a PWB is performed separately upon each of the stacked PWBs prior to the point at which the PWBs are brought together for joining and interconnection. Among the typical processes that each PWN undergoes are: A) circuit printing, B) component stuffing (whether by axial, radial or SMD processes), C) initial testing, D) touch-up fixes, E) final PWB Quality Control, F) inventorying, and G) delivery to final assembly station for interconnection.
It would be advantageous to fully automate the above processes such that no manual manipulation is necessary when bringing the PWBs from inventory or when performing the joining operation itself. Moreover, it would be advantageous to streamline and lower the cost of manufacture, assembly, and testing by creating a process for simultaneous manufacture, assembly, and testing of both boards to be joined such that all phases of manufacture, inventory, final assembly, and testing are performed jointly and automatically. Lastly, it would be advantageous to create specialized tooling that enables the above advantageous processes of the present invention.
One aspect of the present invention is a tool for separating a common printed wiring board substrate into a plurality of substrates having at least one circuit connector connected between the substrates, comprising: a beveled edge of the tool for placement in contact with the substrates to be separated; and at least one notch in the beveled edge for alignment with at least one circuit connector.
Another aspect of the present invention is a process for separating a common printed wiring board substrate into a plurality of substrates having at least one circuit connector connected between the substrates, comprising: forming at least one notch in a beveled edge of a separation tool; aligning at least one notch with at least one circuit connector; and applying pressure between the separating tool and the common substrate.